(1) Team A completed it in 60 days alone 1/60. Team A did it for 20 days first, then cooperated with Team B for 24 days, then Team A did it for 44 days, and the remaining 16/60 was completed by Team B in 24 days, and Team B did 65440 every day.

(2) Team B can't do it alone,

Team A needs 3.5 * 60 = 265438+ 10,000 in 60 days.

Team A and Team B cooperate in the whole process, and complete1/60+1/90 = 5/180 every day.

A * * * need 1÷(5/ 180)=36 days.

The project cost to be paid is 3.5 * 36+2 * 36 = 1.98 million.

So Team A and Team B cooperate to save money.